3x+7 x+3 2x Solve the equation: 5 2 19b) The rate at which a metal bar is changing its temperature in "C (heated or otherwise) over time T is given as a function of time (in minutes): H = T2 - 107 + 21\fii) Determine the range over which H > 21.iii} 'What are the values. [If time when the temperature [If the meta] bar is 5\"\